Telemetric chemical injection assembly

ABSTRACT

A chemical injection assembly with telemetric capacity and a single fluid injection line capable of reaching multiple downhole injection points. The assembly may take advantage of downhole power telemetry modules so as to intelligently power and direct actuator valves at any of a number of different injection points. So, for example, the need for cumbersome and expensive usage of different delivery lines dedicated to serve different delivery points with the same fluid may be avoided.

PRIORITY CLAIM/CROSS REFERENCE TO RELATED APPLICATION(S)

This Patent Document is a Continuation-In-Part claiming priority under35 U.S.C. §120 to U.S. application Ser. No. 13/364,785, entitled“Chemical Injection Regulation Mechanism”, filed Feb. 2, 2012, and whichclaims priority under 35 U.S.C. §119 to U.S. Provisional App. Ser. No.61/438,995, filed on Feb. 3, 2011, and entitled, “Chemical InjectionU-Tube Prevention System”, both of which are incorporated herein byreference in their entireties.

BACKGROUND

Exploring, drilling and completing hydrocarbon wells are generallycomplicated, time consuming and ultimately very expensive endeavors. Asa result, over the years increased attention has been paid to monitoringand maintaining the health of such wells. Significant premiums areplaced on maximizing the total hydrocarbon recovery, recovery rate, andextending the overall life of the well as much as possible. Thus,logging applications for monitoring of well conditions play asignificant role in the life of the well. Similarly, significantimportance is placed on well intervention applications, such asclean-out techniques which may be utilized to remove debris from thewell so as to ensure unobstructed hydrocarbon recovery.

In addition to interventional applications, the well is often outfittedwith chemical injection equipment to enhance ongoing recovery effortswithout the requirement of intervention. For example, most of the wellmay be defined by a smooth steel casing that is configured for the rapiduphole transfer of hydrocarbons and other fluids from a formation.However, a buildup of irregular occlusive scale, wax and other debrismay occur at the inner surface of the casing or tubing and otherarchitecture so as to restrict flow. Such debris may even form overperforations in the casing, screen, or slotted pipe thereby alsohampering hydrocarbon flow into the main borehole of the well from thesurrounding formation.

In order to address the potential for scale and other buildup as notedabove, time consuming interventional applications may be avoided throughuse of a circulating chemical injection system. With such systems inplace, a metered amount of chemical mixture, such as a hydrochloric acidmix, may be near continuously circulated downhole to help prevent suchbuildup. This equipment includes an injection line that may be run fromsurface and directed at different downhole points of interest such aswithin production tubing, at a production screen or into formation fluidprior to entering the noted tubing. Regardless, the need to haltproduction or run expensive interventions in order to addressundesirable buildup may be largely eliminated.

Unfortunately, unlike more interactive interventions, chemical injectionfaces a variety of limitations in terms of delivery. For example, thepermanently installed hydraulic line generally terminates at a portbelow an area of concern such as the indicated production screen.However, this delivery is targeted at a single release point with thesystem relying on circulation of the delivered chemical mix in order toreach any other locations. Thus, even though a variety of locations maybe of potential concern, only the target location is ensured ofreceiving the intended mix with a notable degree of precision.

With the limitations of single port delivery in mind, there arecircumstances in which the delivery line is outfitted with multipledelivery ports such that delivery to more than one location is notlimited to sole reliance on circulation. However, in these situations,the versatility of the delivery nevertheless remains limited. Forexample, where delivery is directed at multiple production zones, theremay be particular zones of concern at one point in time and other zonesof interest at other times. Yet, with a single delivery line available,each port delivers a predetermined rate of chemical mix when directedfrom surface equipment. That is to say, different ports at differentlocations are generally unable to activated while others are leftclosed. Rather, by way of a single delivery line, all ports aregenerally on or all are turned off.

Of course, it may be possible to provide a dedicated delivery line foreach port which runs from surface equipment. In this manner, each linemay be independently turned on or off at surface so as to allow fordownhole ports to be independently activated. However, this type ofsystem would require a dedicated delivery line for each and every port,thus, dramatically increasing completions equipment and installationexpense.

As an alternative to providing a dedicated line running to each portwhere multiple ports are utilized, isolation techniques may be employed.That is, as in the case of stimulation and other zonally directedapplications, different downhole zones may be isolated for sake oftargeted delivery. In such cases, packers or other isolating downholefeatures may be employed as a means of targeting chemical injectiondelivery from multiple ports. For example, one downhole region may beisolated in a manner that prevents chemical delivery thereto whileallowing such delivery elsewhere. Of course, again, shutting downproduction for sake of attaining isolation results in applications thatare no more cost-effective or time saving than the original types ofinterventions which chemical injection systems are configured to helpavoid.

Ultimately, dedicated delivery lines and isolation techniques areusually avoided. As a matter of time and cost, such options remainlargely impractical. Thus, operators are generally left with reliance onsingle or multi-point chemical injection delivery which lacks any realmeasure of control over location specific delivery and/or adjustmentthereto.

SUMMARY

A “smart” chemical injection assembly utilizing telemetry is provided.The assembly includes a mandrel housing coupled to a downhole tubularwith an electric line that runs from an oilfield surface to the mandrelin a land well or offshore well. A fluid injection line is provided thatalso runs from the oilfield surface to the mandrel in a land well oroffshore well. Further, a power telemetry module is coupled to theelectric line. Thus, an electric actuator that is coupled to theinjection line may be provided for governing fluid injection.Additionally, one or both of the module and the actuator may be securedwithin the mandrel housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view of an embodiment of a telemetricchemical injection assembly disposed in a well.

FIG. 2A is an enlarged view of an embodiment of an injection sub of theassembly of FIG. 1 and corresponding downhole fluid flow.

FIG. 2B is an enlarged view of an alternate embodiment of an injectionsub of the assembly with alternate corresponding downhole fluid flow.

FIG. 3 is an overview of an oilfield employing an embodiment of theassembly of FIG. 1 for tailored regulation of injection fluids atmultiple well zones.

FIG. 4A is an alternate embodiment of the injection sub of FIG. 2B,equipped to accommodate a secondary injection line.

FIG. 4B is another alternate embodiment of the injection sub, outfittedwith multiple injection valves.

FIG. 5 is a flow-chart summarizing an embodiment of employing atelemetric chemical injection assembly within a well.

DETAILED DESCRIPTION

Embodiments are described with reference to certain configurations ofcompletions hardware that make use of chemical injection assemblies. Inparticular, completions are depicted and described which utilize achemical injection assembly to help prevent scale and other buildup in amanner that may be telemetrically directed. For example, differentinjection points in different well locations may be independentlydirected from an oilfield surface even though a common injection linemay be utilized. Of course, a variety of different completionarchitectures may benefit from utilization of such an injectionassembly. For example, even a system utilizing a single injection pointmay benefit from telemetrically directed injection. Regardless, aninjection sub (or mandrel housing) is provided that is equipped toaccommodate either, or both, of an actuator valve to govern injectionand a power module. Thus, the valve may be directly and independentlypowered and controlled via telemetric and fluid injection lines runningthereto from surface.

Referring now to FIG. 1, a side cross-sectional view of an embodiment ofa telemetric chemical injection assembly 100 is depicted within a well180. In the embodiment shown, the assembly 100 makes up a portion ofcompletions hardware that is disposed below casing 185 and a productionpacker 110. Further, the assembly 100 is positioned across multipleproduction regions 190, 195. More specifically, a zonal isolation packer120 is provided about a production tubular 107. Thus, separate annularspaces 105, 106 adjacent the tubular 107 may be zonally isolated fromone another whereas a common fluid channel 103 is defined within thetubular 107.

Zonal isolation at production regions 190, 195 as described above mayallow for tailored recovery of production fluids. For example, thetubular 107 may be outfitted with a separate flow control valve 115,116, exposed to the isolated annular space 105, 106. Thus, a hydraulicor other suitable control line 117 may be utilized to independently openor close the valves 115, 116. As such, production through a slottedliner 187, screen, perforated liner or similar hardware where utilized,at either formation region 190, 195 may be regulated via the open orclosed valve 115, 116.

Continuing with reference to FIG. 1, each zonally isolated annular space105, 106 is equipped with its own mandrel housing or injection sub 101,102. As such, a chemical injection fluid mix may be directed at eachspace 105, 106, the liner 187 or other downhole hardware so as to impedeproduction inhibiting buildup. In one embodiment, the mix may even bedirected internally at the tubular channel 103 (see FIG. 2B).Regardless, while separate injection points 161, 163 are provided,independent control over the separate valves 160, 162 at each point 161,163 is a different matter. That is, in the embodiment shown, the valves160, 162 may be an electrically powered actuator of plunger, gas lift,solenoid valve, electric motor or other metering variety. Thus, ratherthan opening or closing alone, more precise delivery of chemicalinjection mix may be achieved. So, for example, the valves may includefully opened, fully closed and variable choke positions.

Further, while it might be possible to supply each valve 160, 162 withits own dedicated fluid line which may be controlled from the oilfieldsurface 300, this may be extremely cost prohibitive (see FIG. 3).Therefore, the embodiment of FIG. 1 reveals the use of a singleinjection line 150 routed to each valve 160, 162 in combination with atelemetric line 155 so as to more fully and practically take advantageof such tailored delivery.

The telemetric line 155 of FIG. 1 may be a conventional electric line orother suitable communication line for downhole use. In the embodimentshown, the line 155 is routed through a power telemetry module 170, 171in order to supply the power for independently opening or closing eachvalve 160, 162 as directed. These modules 170, 171 are shown disposedwithin the subs 101, 102. However, in other embodiments, alternativelocations may be utilized. Further, such modules 170, 171 may be madeavailable for sake of monitoring and communicating downhole conditionssuch as pressure and/or temperature. Thus, an added feature of suchmodules 170, 171 may now be to advantageously serve as a supportiveplatform for independent powerable control over each valve 160, 162 in a“smart” fashion.

Referring now to FIG. 2A, an enlarged view of an embodiment of one ofthe injection subs 102 of the assembly of FIG. 1 is shown. In thisdepiction, fluid flow in the area is apparent. More specifically,production fluid 250 is shown moving uphole within the channel 103 ofthe production tubular 107 whereas injection fluid 200 is shown releasedfrom the valve 162 at the injection point 163. So, for example, theinjection fluid 200 may serve to prevent occlusive buildup at the wellformation interface of the slotted liner 187 and the depicted productionregion 195. Thus, when the flow control valve 116 is opened, productionfluid 250 may flow substantially freely into the noted channel 103.Further, in one embodiment, an operator or control unit 310 may ensurethat the flow control valve 116 is in an open or ‘choked’ positionwhenever the injection valve 162 is in an open position (see FIG. 3).

Continuing with reference to FIG. 2A, with added reference to FIG. 1, ashiftable member 216 of the flow control valve 116 may be directed toopen the valve 116 by a conventional control line 117. For example, aconventional power/data cable may be utilized. However, opening of theinjection valve 162 for sake of chemical injection delivery is two-fold.That is, the valve 162 may be supplied with the noted injection fluid200 by way of the noted injection line 150. Further, tailored controlover opening and/or the degree of opening of the valve 162 may bedirected by another line (i.e. the telemetric line 155). While theinjection and telemetry functions are split between two separate lines150, 155, this type of layout allows for the use of a single injectionline 150 across multiple subs 101, 102. That is, a tailored openingand/or closing of valves such as the injection valve 162 may beindependently controlled. Therefore, even though only a single injectionline 150 is utilized, the operator is not limited to an unintelligentinjection of either all injection points 161, 163 open or all closed.

As described above, the independent control over chemical injectiondelivery is directed through a telemetric line 155. This may be aconventional electronic or other suitable cable. Once more, the line 155may be routed from surface to a power telemetry module 171 as detailedabove. That is, the module 171 may serve a function of acquiring andrelaying data relative to temperature, pressure and perhaps otherlocation-based well characteristics (note the exposed outlet to thetubular channel 103). However, the module 171 may also advantageouslyserve the added function providing power and communicative relay to theinjection valve 162 (note the electrical branch 255 of the line 155routed to the valve 162). Thus, independent control over the valve 162may be exercised from the oilfield surface 300. Indeed, with multiplemodules 170, 171 available, this same type of telemetric layout may berepeated at multiple downhole subs 101, 102 (see FIG. 1). As such,independent “intelligent” control over each valve 160, 162 by way of asingle main telemetric line 155 may be provided (see FIG. 3).

Referring now to FIG. 2B, an enlarged view of an alternate embodiment ofthe injection sub 102 is depicted. In this embodiment, the injectionvalve 162 and injection point 163 are reoriented so as to deliverinjection fluid 200 within the channel 103 of the production tubing 107as opposed to at the surrounding annular space 106. For example, thismay be advantageous where the sub 102 is located further uphole adjacentwell casing 185. That is, the fluid 200 may be directed at impedingbuildup at internal tubular components as opposed to the slotted liner187 as shown in FIG. 2A. Regardless, the same intelligent, independentlycontrollable manner of injection may be directed from the oilfieldsurface 300 of FIG. 3.

Continuing now with reference to FIG. 3, an overview of an oilfield 300is shown, whereat an embodiment of the assembly 100 of FIG. 1 isdisposed within a well 180. More specifically, a more schematic view ofthe assembly 100 is shown allowing for tailored regulation of injectionfluid 200 at different downhole production regions 190, 195. Morespecifically, production and chemical injection are both closed offrelative the more downhole region 195. For example, where water is beingproduced or for any number of other reasons, a determination may be madeto effectively shut off the region 195. Nevertheless, a determination tocontinue recovery of production fluids from points below the region 195may also be made. Further, and perhaps more significantly in terms ofthe depicted figure, a determination may similarly be made to continuerecovery and chemical injection at the other region 190.

In the embodiment of FIG. 3, chemical injection fluid 200 is deliveredin the vicinity of one region 190 so as to inhibit buildup at theslotted liner or screen or perforated liner 187 as described above. Thissame fluid 200 is recovered within the tubular 107 along with productionfluids 250 for transport uphole. The ability of the assembly 100 toefficiently recover these fluids 200, 250 at one region 190 whilekeeping injection and recovery closed off from another region 195 isrendered practical and effective by the availability of cooperativevalves 160, 162 and modules 170, 171 as detailed hereinabove (see FIG.1). Indeed, an electrically actuated plunger type valve 160, 162 inconjunction with a readily available power telemetry module 170, 171 maybe particularly beneficial in allowing for the construction of such anassembly 100.

Continuing with reference to FIG. 3, an operator may intelligentlydirect chemical injection as detailed above through the use of surfaceequipment. More specifically, a control unit 310 may be provided forsake of directing operations, including the exercise of control over thetelemetric line 155 and downhole valves as detailed above. Further, achemical mix tank 320 may be provided for supplying of injection fluid200 to the injection line 150. Thus, later recovery of injection 200 andproduction 250 fluids may ultimately be routed through the well head 330and a production line 340 for processing.

Referring now to FIG. 4A, an alternate embodiment of the injection sub102 and assembly 100 of FIG. 2B is shown. In this embodiment, asecondary line 400 is routed to the location of the injection valve 162.In this manner, a fluid other than the chemical injection fluid 200 mayalso be delivered through the valve 162. That is, while fluid of anypractical type may be directed through the injection line 150, there maybe circumstances in which different fluid types are segregated from oneanother. For example, an acid injection type of stimulation fluid may bedelivered through the secondary line 400 at certain targeted points intime whereas the noted injection fluid 200 is delivered through theinjection line 150 on a more regular or continuous basis.

Keeping fluids separated from one another may be desirable where thedifferent fluids serve different applications, for example, differentchemical injection and stimulation applications as noted above. However,it is worth noting that the added secondary line 400 is not required forsake of delivery to different injection points 161, 163 (see FIG. 1).Indeed, as depicted in FIG. 4A, even though separate fluid types andlines 150, 400 are provided, the same injection point 163 is ultimatelyutilized.

Referring now to FIG. 4B, another alternate embodiment of the injectionsub 102 is depicted. In this case, the sub 102 is outfitted withmultiple injection valves 162, 462, 463 all drawing actuation from thesame power telemetry module 171. For example, note the electrical branch255 running to the primary injection valve 162 as detailed above, aswell as a secondary branch 455 splitting off to other secondaryinjection valves 462, 463.

In the embodiment of FIG. 4B, the availability of multiple valves 162,462, 463 allows for targeting of different delivery locations. That is,embodiments such as that depicted in FIG. 1 reveal different subs 101,102 at different depths being independently serviceable via a singleinjection line 150. However, in FIG. 4B another embodiment is shown thatreveals the possibility of also servicing different locations at roughlythe same depth of the same sub 102. More specifically, the primaryinjection valve 162 is shown servicing the channel 103 at the interiorof the production tubular 107 similar to the configuration of FIG. 2B.Further, the secondary valves 462, 463 are shown simultaneouslyservicing the annular space 106 similar to the configuration of FIG. 2A.

Referring now to FIG. 5, a flow-chart is shown summarizing an embodimentof employing a telemetric chemical injection assembly within a well.Namely, with the assembly installed as indicated at 510, a chemicalinjection fluid may be selectively delivered through a line to any oneof many injection points downhole (see 530). Subsequently, over the sameline, the fluid may be delivered to another of the points as indicatedat 550. Once more, as noted at 570, these same injection points may beserviced by a secondary line for delivery of another fluid such as anacid-based stimulation fluid. Ultimately, over the course of such fluiddelivery applications, the fluids may be recovered with production up toan oilfield surface as indicated at 590.

Embodiments described hereinabove include a telemetric or “smart”chemical injection assembly which is able to provide targeted chemicalinjection at multiple downhole depths or locations in a tailored manner.That is, without the requirement of a multitude of individuallydedicated chemical injection lines, multiple delivery locations may beindependently regulated for delivery from an oilfield surface. Further,no intervening isolations are required in order to achieve such targetedor tailored delivery. Indeed, one downhole location may be opened andserviced while another remains turned off and vice versa. This may beachieved in a cost-effective manner through the use of available powertelemetry modules.

The preceding description has been presented with reference to presentlypreferred embodiments. Persons skilled in the art and technology towhich these embodiments pertain will appreciate that alterations andchanges in the described structures and methods of operation may bepracticed without meaningfully departing from the principle, and scopeof these embodiments. Regardless, the foregoing description should notbe read as pertaining only to the precise structures described and shownin the accompanying drawings, but rather should be read as consistentwith and as support for the following claims, which are to have theirfullest and fairest scope.

1. A telemetric chemical injection assembly for disposal in a well at anoilfield, the assembly comprising: an injection sub; an actuator valvedisposed within said sub to govern fluid injection therefrom; a powerand telemetry module coupled to said valve; a telemetric line configuredto run from a surface of the oilfield to said module; and a fluidinjection line configured to run from a surface of the oilfield to saidvalve for the fluid injection.
 2. The assembly of claim 1 wherein saidmodule is disposed within said sub.
 3. The assembly of claim 1 whereinsaid module serves as a monitor for well conditions.
 4. The assembly ofclaim 3 wherein the well conditions include one of pressure andtemperature.
 5. The assembly of claim 1 wherein said actuator valve iselectrically powered via said module.
 6. The assembly of claim 1 whereinsaid actuator valve is selected from a group consisting of a plungervalve, a sliding sleeve, a gas lift valve, a solenoid valve, an electricmotor and a metering valve.
 7. The assembly of claim 1 wherein the fluidinjection line is configured to supply a chemical injection fluid mix tosaid valve.
 8. The assembly of claim 1 further comprising a secondaryline configured to run from a surface of the oilfield to said valve forsupplying of a secondary fluid.
 9. The assembly of claim 8 wherein thesecondary fluid is a stimulation fluid.
 10. The assembly of claim 1wherein said sub and said actuator valve are a first sub and a firstactuator valve, the assembly further comprising a second actuator valvecoupled to said injection line disposed within a second sub at adifferent depth of the well than said first sub.
 11. The assembly ofclaim 1 wherein said valve is a first valve, the assembly furthercomprising a second valve coupled to said injection line within the sub.12. A telemetric chemical injection system comprising for disposal in awell at an oilfield, the system comprising: a tubular with a channelrunning therethrough and disposed within the well, the well defined bymultiple formation regions; a zonal isolation packer defining a firstannulus thereabove and a second annulus therebelow, said packerpositioned at a depth between at least portions of the regions; a firstinjection sub and power module coupled to said tubular within the firstannulus; a second injection sub and power module coupled to said tubularwithin the second annulus; a telemetric line configured to run from asurface of the oilfield to said modules; and a fluid injection lineconfigured to run from the oilfield surface to said subs.
 13. The systemof claim 12 further comprising: a first flow control valve incorporatedinto said tubular at a location of the first annulus; and a second flowcontrol valve incorporated into said tubular at a location of the secondannulus.
 14. The system of claim 12 wherein said subs comprise actuatorvalves for delivery of fluid from the fluid injection line.
 15. Thesystem of claim 14 wherein the delivery is directed at one of thechannel and a formation interface with the well.
 16. A method ofdelivering chemical injection fluid to a well at an oilfield, the methodcomprising: directing an actuator valve to open from a surface of theoilfield over a telemetric line running therefrom: powering saiddirecting through a power telemetry module coupled to the telemetricline and the valve; and supplying the fluid for the delivering through afluid injection line coupled to the valve.
 17. The method of claim 16wherein the actuator valve is a first actuator valve, said directingfurther comprising maintaining closure of a second actuator valvecoupled to the telemetric and fluid injection lines.
 18. The method ofclaim 16 wherein the actuator valve is a first actuator valve, saiddirecting further comprising opening a second actuator valve coupled tothe telemetric and fluid injection lines.
 19. The method of claim 16further comprising supplying another fluid through a secondary injectionline coupled to the valve for another application.
 20. The method ofclaim 16 further comprising recovering fluids including the injectionfluid through production to a surface at the oilfield.